Alternating current

ACalternating-currentalternatingalternating electric currentA.C.AC mainsAC currentalternating current (AC)AC voltageA.C
Alternating current (AC) is an electric current which periodically reverses direction, in contrast to direct current (DC) which flows only in one direction.wikipedia
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Direct current

DCdirect-currentDC current
Alternating current (AC) is an electric current which periodically reverses direction, in contrast to direct current (DC) which flows only in one direction.
The electric current flows in a constant direction, distinguishing it from alternating current (AC).

Electric current

currentelectrical currentcurrents
Alternating current (AC) is an electric current which periodically reverses direction, in contrast to direct current (DC) which flows only in one direction. The abbreviations AC and DC are often used to mean simply alternating and direct, as when they modify current or voltage.
In alternating current (AC) systems, the movement of electric charge periodically reverses direction.

High-voltage direct current

high voltage direct currentHVDChigh-voltage direct-current
High-voltage direct-current (HVDC) electric power transmission systems have become more viable as technology has provided efficient means of changing the voltage of DC power.
A high-voltage, direct current (HVDC) electric power transmission system (also called a power superhighway or an electrical superhighway) uses direct current for the bulk transmission of electrical power, in contrast with the more common alternating current (AC) systems.

Guitar amplifier

amplifiersamplifierguitar amplifiers
In certain applications, like guitar amplifiers, different waveforms are used, such as triangular or square waves.
When engineers developed the first AC mains-powered amplifiers, they were soon used to make musical instruments louder.

Three-phase electric power

three-phasethree-phase powerthree phase
Three-phase electrical generation is very common.
Three-phase electric power is a common method of alternating current electric power generation, transmission, and distribution.

Radio frequency

RFradio frequenciesradio-frequency
Audio and radio signals carried on electrical wires are also examples of alternating current. Litz wire is used for making high-Q inductors, reducing losses in flexible conductors carrying very high currents at lower frequencies, and in the windings of devices carrying higher radio frequency current (up to hundreds of kilohertz), such as switch-mode power supplies and radio frequency transformers.

Single-phase electric power

single-phasesingle phase1 phase
For smaller customers (just how small varies by country and age of the installation) only a single phase and neutral, or two phases and neutral, are taken to the property.
In electrical engineering, single-phase electric power is the distribution of alternating current electric power using a system in which all the voltages of the supply vary in unison.

Electric generator

generatorgeneratorselectrical generator
In a power plant, energy is generated at a convenient voltage for the design of a generator, and then stepped up to a high voltage for transmission.
A coil of wire rotating in a magnetic field produces a current which changes direction with each 180° rotation, an alternating current (AC).

Electric power transmission

transmissionpower linespower line
Transmission with high voltage direct current was not feasible in the early days of electric power transmission, as there was then no economically viable way to step down the voltage of DC for end user applications such as lighting incandescent bulbs.
Most transmission lines are high-voltage three-phase alternating current (AC), although single phase AC is sometimes used in railway electrification systems.

Split-phase electric power

split phasesplit-phasemultiwire branch circuit
Three-wire single-phase systems, with a single center-tapped transformer giving two live conductors, is a common distribution scheme for residential and small commercial buildings in North America.
It is the AC equivalent of the original Edison three-wire direct-current system.

Utility frequency

50 Hzfrequencymains frequency
The frequency of the electrical system varies by country and sometimes within a country; most electric power is generated at either 50 or 60 Hertz.
The utility frequency, (power) line frequency (American English) or mains frequency (British English) is the nominal frequency of the oscillations of alternating current (AC) in an electric power grid transmitted from a power station to the end-user.

Electric power

powerelectrical powerelectrical
Alternating current is the form in which electric power is delivered to businesses and residences, and it is the form of electrical energy that consumers typically use when they plug kitchen appliances, televisions, fans and electric lamps into a wall socket.
In alternating current (AC) circuits the direction of the voltage periodically reverses, but the current always flows from the higher potential to the lower potential side.

Harmonics (electrical power)

harmonicsharmonicharmonic currents
Non-linear loads (e.g. the switch-mode power supplies widely used) may require an oversized neutral bus and neutral conductor in the upstream distribution panel to handle harmonics.
In a normal alternating current power system, the current varies sinusoidally at a specific frequency, usually 50 or 60 hertz.

Ground and neutral

neutralneutral wireground
A third wire, called the bond (or earth) wire, is often connected between non-current-carrying metal enclosures and earth ground.
Ground or earth in a mains (AC power) electrical wiring system is a conductor that provides a low-impedance path to the earth to prevent hazardous voltages from appearing on equipment (high voltage spikes).

Electrical resistance and conductance

resistanceelectrical resistanceconductance
This allows the power to be transmitted through power lines efficiently at high voltage, which reduces the energy lost as heat due to resistance of the wire, and transformed to a lower, safer, voltage for use.
Another situation for which this formula is not exact is with alternating current (AC), because the skin effect inhibits current flow near the center of the conductor.

Skin effect

skin depthconductor skin effectscurrents tend to flow on the surface of conductors
This phenomenon is called skin effect.
Skin effect is the tendency of an alternating electric current (AC) to become distributed within a conductor such that the current density is largest near the surface of the conductor, and decreases with greater depths in the conductor.

Ripple (electrical)

rippleripple currentripples
Computer mainframe systems were often powered by 400 Hz or 415 Hz for benefits of ripple reduction while using smaller internal AC to DC conversion units.
Ripple (specifically ripple voltage) in electronics is the residual periodic variation of the DC voltage within a power supply which has been derived from an alternating current (AC) source.

Electrical injury

electric shockelectrocutionelectrocuted
This significantly reduces the risk of electric shock in the event that one of the live conductors becomes exposed through an equipment fault whilst still allowing a reasonable voltage of 110 V between the two conductors for running the tools.
The minimum current a human can feel depends on the current type (AC or DC) as well as frequency for AC.

Litz wire

Litz conductors
Wire constructed using this technique is called Litz wire.
Litz wire is a special type of multistrand wire or cable used in electronics to carry alternating current (AC) at radio frequencies.

Voltage

potential differenceVvoltages
The abbreviations AC and DC are often used to mean simply alternating and direct, as when they modify current or voltage.
When talking about alternating current (AC) there is a difference between instantaneous voltage and average voltage.

Traction motor

traction motorsMotormotors
A low frequency eases the design of electric motors, particularly for hoisting, crushing and rolling applications, and commutator-type traction motors for applications such as railways.
The availability of high-powered semiconductors (thyristors and the IGBT) has now made practical the use of much simpler, higher-reliability AC induction motors known as asynchronous traction motors.

Inductor

inductorscoilinductive
Litz wire is used for making high-Q inductors, reducing losses in flexible conductors carrying very high currents at lower frequencies, and in the windings of devices carrying higher radio frequency current (up to hundreds of kilohertz), such as switch-mode power supplies and radio frequency transformers.
Inductors are widely used in alternating current (AC) electronic equipment, particularly in radio equipment.

Rail transport

railwayrailroadrail
A low frequency eases the design of electric motors, particularly for hoisting, crushing and rolling applications, and commutator-type traction motors for applications such as railways.
The first practical AC electric locomotive was designed by Charles Brown, then working for Oerlikon, Zürich.

Electrical conductor

conductorconductiveconductors
Even at relatively low frequencies used for power transmission (50 Hz – 60 Hz), non-uniform distribution of current still occurs in sufficiently thick conductors.
Another situation this formula is not exact for is with alternating current (AC), because the skin effect inhibits current flow near the center of the conductor.

Overhead power line

power linepower linespowerline
This allows the power to be transmitted through power lines efficiently at high voltage, which reduces the energy lost as heat due to resistance of the wire, and transformed to a lower, safer, voltage for use.
1891 saw the construction of the first three-phase alternating current overhead line on the occasion of the International Electricity Exhibition in Frankfurt, between Lauffen and Frankfurt.